FORMATION OF PHENOL IN DEGRADATION OF P-HYDROXYBENZOIC ACID BY KLEBSIELLA AEROGENES (AEROBACTER AEROGENES)

After growth of K. aerogenes in chemically defined media consisting of mineral salts and p-hydroxybenzoate with or without glucose, phenol was found in the culture fluid at concentrations inhibiting further growth. Bacteria adapted to mineral salts medium containing p-hydroxybenzoate as sole source of carbon and energy produced small but isolable quantities of 3,4-dihydroxybenzoic acid and catechol and oxidized these substances as rapidly as p-hydroxybenzoate. Bacteria adapted to mineral salts medium containing glucose as sole carbon and energy source did not oxidize p-hydroxybenzoate, 3,4-dihydroxybenzoate or catechol. Bacteria adapted to glucose medium or to p-hydroxybenzoate medium did not oxidize or utilize phenol as sole carbon and energy source. A metabolic pathway for p-hydroxybenzoate degradation is proposed and the formation of phenol is attributed to a side reaction. © 1969 Swets & Zeitlinger.